Merge pull request #35 from CCRI-POPROX/karl/refactor/repository-regi…

…stration

Auto-register `DatabaseRepository` sub-classes to create with decorator

src/poprox_storage/repositories/data_stores/db.py

@@ -1,5 +1,6 @@
 import logging
-from typing import Any
+from functools import wraps
+from typing import Any, get_type_hints
 from uuid import UUID
 
 from sqlalchemy import (
@@ -16,10 +17,39 @@
 logger.setLevel(logging.DEBUG)
 
 
+def inject_repos(handler):
+    @wraps(handler)
+    def wrapper(event, context):
+        with DB_ENGINE.connect() as conn:
+            params: dict[str, type] = get_type_hints(handler)
+            # remove event, context, and return type if they were annotated.
+            params.pop("event", None)
+            params.pop("context", None)
+            params.pop("return", None)
+
+            repos = dict()
+            for param, class_obj in params.items():
+                if class_obj in DatabaseRepository._repository_types:
+                    repos[param] = class_obj(conn)
+
+            return handler(event, context, **repos)
+
+    return wrapper
+
+
 class DatabaseRepository:
+    _repository_types = set()
+
     def __init__(self, connection: Connection):
         self.conn: Connection = connection
 
+    def __init_subclass__(cls, *args, **kwargs):
+        """
+        Gets called once for each loaded class that sub-classes DatabaseRepository
+        """
+
+        cls._repository_types.add(cls)
+
     def _load_tables(self, *args) -> dict[str, Table]:
         metadata = MetaData()
         tables = {}

tests/test_repositories.py

@@ -0,0 +1,16 @@
+from poprox_storage.repositories import DbArticleRepository
+from poprox_storage.repositories.data_stores.db import inject_repos
+from poprox_storage.repositories.newsletters import DbNewsletterRepository
+
+
+@inject_repos
+def example(event, context, article: DbArticleRepository, newsletter_repo: DbNewsletterRepository):
+    return article, newsletter_repo
+
+
+def test_repositories():
+    retval = example({}, {})
+    assert isinstance(retval, tuple)
+    assert len(retval) == 2
+    assert isinstance(retval[0], DbArticleRepository)
+    assert isinstance(retval[1], DbNewsletterRepository)